Backstop positioning gage



July 1, i969 c, BAKER 3,452,441

BACKSTOP POSIT IONING GAGE Filed Nov. 6, 1967 flax)? er 5. 50046/ INVENIOR.

ATTOR/WEVJ US. Cl. 33185 9 Claims ABSTRACT OF THE DISCLOSURE The press brake backstop positioning gage disclosed is formed of a pair of parallel-extending indexing plates resiliently mounted with respect to each other. The lower indexing plate is designed to extend across the female die of the press brake and the upper indexing plate has a pair of V-shaped notches designed to engage the male die member thereby establishing a reference plane coplanar with the centerline of the male die member and providing a basis of reference for measuring to a backstop. A scale, extending perpendicular to the reference plane, is slidingly mounted in the lower indexing plate, and means are provided to releasably secure it at any desired position. Indicia, aligned with the apex of the notch, provides a reference point for measuring to the backstop. -In addition to the indicia, there is a removablymounted reference block which includes allowance for the bend and the gage of the material being bent.

The present invention relates to a backstop positioning gage for a press brake and more particularly to a backstop positioning gage which is referenced relative to the male die member of the press brake.

Press brakes are used in the sheet metal industry to form angle bends or flanges in metal. A press brake has a female V-die, which is generally stationarily installed in the bed of the press brake, and a male V-die, which is reciprocatingly mounted in the press brake for movement toward and away from the female die. In some installations, the dies may be twelve or more feet long. In such cases, it is most diflicult to properly align the dies so that their longitudinal centerline will be colinear.

The metal to be bent is positioned over the face of the female die and extends outward thereof until it contacts adjustable backstops which are located laterally outwardly of the longitudinal centerlines of the dies. When forming a flange having a predetermined height, the distance from the backstops to the centerlines of the dies must be equal to the desired flange height less certain allowances which are well known in the industry. These allowances include an allowance for the gage of the metal being bent and a bend allowance. Since the positioning of the backstops determines the position of the workpiece relative to the dies, it is necessary that the backstops be properly positioned.

The customary procedure for setting up a press brake is to first determine the distance from the end of the material to the breakline (the theoretical common centerline of the dies) and then to scribe a line representing such breakline on a piece of sheet material. The material is then set in the press brake so that the breakline inscribed in the material registers with the centerline of the male and female dies. The backstops of the press brake are then set against the outwardly-extending edge of the material and the flange is formed by operating the brake. In the majority of cases, the first setting of the backstops will not be precisely correct due to the difficulty of registering the centerlines of the dies with the inscribed breakline. As a result of the inherent inaccuracy of this method, it is usually necessary to make several adjustments, each using a fresh piece of sheet material nitecl States Patent in order to obtain the required accuracy. Thus, this procedure is not only wasteful of time and effort but it also is wasteful of material. Moreover, such a procedure generally requires the services of a skilled mechanic who knows how to calculate the proper bend and material allowances. Accordingly, various types of gages have been proposed by which the backstops may be set without following the above procedure; however, as far as is known, all such gages are referenced with respect to the female die.

The location of the break in the material is caused primarily by the nose of the male die and a certain amount of misalignment of the female die relative to the male die can be tolerated. Therefore, it is desirable that in utilizing a gage for setting the backstop that such gage be referenced in relation to the male die. Accordingly, it is an object of the present invention to provide a backstop positioning gage for a press brake which indexes off the male die of the press brake.

It is another object to provide a backstop positioning gage for a press brake in which the indexing portion establishes a reference plane coplanar with the longitudinal centerline of the male die member.

It is still another object to provide a backstop positioning gage for a press brake in which the indexing portion of the gage establishes a three-point contact with the cooperating dies.

It is a further object to provide a backstop positioning gage for a press brake in which the indexing portion is formed to permit its insertion between dies having a lesser distance between them than the expanded distance of the indexing portion.

:It is still a further object to provide a backstop positioning gage for a press brake which has provisions for removably clamping a reference block which includes an allowance for the bend and the gage of the material being bent to establish an indicia for measuring means extending outwardly of the gage which reflects the true numerical distance to the backstop.

The above objects, and other objects relating to details of manufacture and use which will become apparent to those skilled in the art from the specification and drawings to follow, may be accomplished by forming a backstop positioning gage of an indexing portion formed of a pair of parallel-extending, resiliently-mounted, indexing plates. The first plate is designed to extend across the face of the female die and the second plate is provided with means to engage the nose of the male die. Accordingly, the indexing portion of the gage has a threepoint contact, one on either side of the V-shaped groove of the female die and one with the male die. Moreover, such portion is also indexed with respect to the male die. Therefore, a reference plane is established which is coplanar with the longitudinal centerline of the male die. Slidingly attached to the first plate is a scale which can be set to indicate the distance to the backstop. Also provided is a resiliently-clamped indexing member which takes into account the bend allowance and the allowance for the gage of the material being bent.

Brief description of the drawings FIG. 1 is a top plan view illustrating the backstop positioning gage of the present invention positioned in a press brake;

FIG. 2 is a front view taken generally along lines 2-2 of FIG. 1; and

FIG. 3 is a sectional view taken generally along lines 33 of FIG. 1; and

FIG. 4 is an enlarged isometric view illustrating the clamping of the reference block.

Description of the preferred embodiment Referring now to the drawings and particularly to FIGS. 1-3, it can be seen that a press brake is comprised of a longitudinally extending female die 12 which is stationarily positioned in the bed of the press brake. Positioned above the female die 12 and mounted for reciprocatory movement toward and away from the female die is a male die 14 which is adapted to cooperate with the female die 12 to form the bend. The female die is provided with a generally upwardly-opening V-shaped groove 16 while the male die is provided with a downwardly directed V-shaped nose portion 18 adapted to enter and mate with groove 16. A plurality of adjustable backstops 20 are positioned perpendicularly outwardly of the longitudinal centerlines of the dies.

In operation, the material to be bent is positioned across the face of the female die. The material extends outwardly until it contacts the backstops. While it is desirable that the male and female dies be in perfect alignment, it has been found that such alignment is most difficult and in many instances the two dies are not in absolute perfect alignment. Although the bend in the material results from the cooperative action of the two die members, it has been found that the location of the break in the material results primarily from the nose of the male die and that, within a small range a certain amount of misalignment of the female die can be tolerated. Therefore, it is desirable in setting up the press brake that the positioning of the backstops 20 be referenced from the nose of the male die 14.

As can be seen in FIG. 3, the backstop positioning gage 22 is formed of an indexing portion having a pair of parallel-extending, resiliently-mounted, indexing plates or members 24 and 26. The lower plate 24 extends across the face of the female die 12 and the upper plate 26 is provided with a pair of V-shaped notches 28 to engage the nose of the male die 14. In such manner, the gage is referenced by the male die 14 so that a reference plane is established which is coplanar with the longitudinal centerline of the male die member. Moreover, the two indexing plates 24 and 26 have a three-point contact with the die members thereby aligning the reference plane with the vertical plane of the dies. Accordingly, an accurate basis of reference for positioning backstop 20 is established. Moreover, the indexing portion is referenced in respect to the dies at the same points of contact that the workpiece will be contacted by the dies.

Means are provided for connecting together the indexing members in such a manner that they can be moved toward and away from each other and preferably such connecting means includes resilient means biasing the indexing members away from each other toward an expanded position. Thus indexing plate 24 can be provided with a downwardly-depending portion 30' in which is located a pair of apertures having a sliding fit with guide members 3434. The upper end of each guide member 34 is secured to the upper plate 26 by a press fit, or other well known means of attaching a member to a plate such as threading or welding may be utilized. The guide members retain upper plate 24 in parallel relation with lower plate 26. Depending portion 30 is also provided with a second pair of apertures 35-35 in which are positioned a second pair of sliding members 36-36. The apertures 35-35 are counterbored and spring members 3838 which resiliently mount the plates with respect to each other are located in the counterbored portion surrounding sliding members 36-36.

Lower plate 24 is provided with a slot 40 which is of suflicient width to receive one of the backstops 20 when the latter are to be set close to the dies for narrow flange bends. Slidingly mounted with respect to the indexing members for movement perpendicular to the referencing plane R is a measuring means 42 which is provided with numerical designations. While a numerical scale is shown,

it is to be understood that other means may be used such as a piece of stock having the desired distance indicated thereon. To securely retain the scale in any desired position, lower plate 24 is provided with a slot extension 40a which has a scale-locking means 44- which may be formed of a bow spring 46. A bridge member 47 is attached to the rear end ofplate 24 and a threaded member 48 which engages spring 46 is threadedly engaged in bridge member 47. By tightening threaded member 48, the scale is retained in position, and by loosening it, sliding movement of scale 42 is permitted.

The lower plate is provided with an indicia 52 aligned with the apex of V-shaped notches 28 and, in effect, is the reference plane established by the indexing portion. However, the distance which the workpiece extends past the centerline of the nose of the male die until it contacts the backstop is not the same numerical distance as the height of the finished flange. Therefore, adjacent to indicia 52, the lower plate is provided with a recess 54. Adjacent to the recess there is a counterbore 56 having one side open to recess 54. A spring clip 58 is clamped in counterbore 56 by a threaded member 60 (see FIG. 4) so that a portion of the clip extends into recess 54. A reference block 62 which takes into account the various factors utilized in figuring out the various allowances, such as bend allowance and allowance for gage of the material being bent, is positioned in recess 54 and is resiliently held in position by the portion of clip 58 which extends into recess 54. A number of such blocks sized for various gages of material normally are provided. Therefore, the numerical distance which the scale extends past the outer edge of reference block 62 will be the finished height of the flange. In other words, if it is desired to produce a four and three-quarter inch flange in .10-gauge material, the lO-gauge reference block will be positioned in the recess and the scale will be set at four and three-quarter inches, see FIG. 4.

To set up a press brake with the backstop positioning gage 22 of the present invention, the proper reference block is positioned in the gage and the scale set to the proper distance, and the gage is then ready for use. The male die 14 of the press brake is lowered to a position slightly above the female die 12. Indexing plates 24 and 26 are then manually moved as close together as possible so that the gage is in a collapsed position and the gage is inserted between the dies. The lower plate 24 of the gage is placed over the face of female die 12 and the gage is permitted to expand until notches 2-8 of the upper plate are engaged with the nose of the male die. In this manner, the gage is properly aligned with the die members and a reference plane R is established coplanar with the longitudinal centerline of the male die. Since the desired distance is already set on scale 42, adjustable backstop 20 may be properly located by bringing the backstop into contact with the end of the scale. Since measuring means 42 extends perpendicularly of the reference plane, the distance to the backstop may be accurately determined. The indexing portion of the gage is compressed and the gage removed from the press brake. The same procedure is then followed to set the other backstops. Inasmuch as the indexing plates are resiliently mounted in parallel relation, the indexing part will have a three-point contact with reference to the die members so that the reference plane established will be coplanar with the vertical plane of the dies. As previously mentioned, the reference plane will also be coplanar to the centerline of the male die, therefore the setting of the backstop will reflect the proper distance for the end of the material to be located in order to provide the desired flange.

The gage can, of course, be used to set front stops on a press brake.

From the foregoing it will be seen that this invention is one well adapted to attain all of the ends and objects hereinabove set forth, together with other advantages which are obvious and which are inherent to the apparatus.

As many possible embodiments may be made of the invention without departing from the scope thereof, it is to be understood that all matter herein set forth or shown in the accompanying drawings is to be interpreted as illustrative and not in a limiting sense.

I claim:

1. For a press brake having a pair of longitudinally extending die members, one being a female die and the other being a male die having a nose portion for cooperation with the female die and at least one adjustable stop located laterally outwardly of the longitudinal centerline of the die members, a stop positioning gage com prising: a first indexing member having a portion to extend over the face of the female die member, to engage points on opposite sides thereof, a second indexing member having means to engage the nose portion of the male die member to establish a reference plane coplanar with the longitudinal centerline of the male die member; means connecting the indexing members for movement toward and away from each other; and measuring means carried by one of said indexing members and extending perpendicularly outward from said reference plane for engagement by the adjustable stop.

2. The stop positioning gage specified in claim 1 wherein the measuring means includes a scale mounted on the first indexing member for sliding movement relative thereto and means releasably clamping said scale to said first indexing member.

3. The backstop positioning gage specified in claim 2 wherein the second indexing member is provided with a removable reference block which reflects the allowance for the bend and the gage of the material being bent, said reference block having an edge adjacent the scale so that such edge is an indicia for the measuring means.

4. The backstop positioning gage specified in claim 3 wherein there is a recess in the first indexing member to receive the reference block and a counterbore is located in the first indexing member adjacent the recess, a portion of the counterbore being open to the recess, a resilient member positioned in said counterbore, a portion of the resilient member extending into the recess and engaging the reference block to retain it in position.

5. The backstop positioning gage specified in claim 1 wherein the means for engaging the nose portion of the male die is a pair of V-shaped notches.

6. The backstop positioning gage specified in claim 1 wherein said connecting means includes resilient means biasing the indexing members away from each other whereby the indexing members may be manually moved toward each other to insert the gage between said dies and then expanded by the resilient means to hold the gage in position.

7. The backstop positioning gage specified in claim 6 wherein the connecting means includes a pair of guide members which extend from one indexing member to the other to retain the indexing members in parallel relation.

8. For a press brake having a pair of longitudinally extending die members, one being a female die and the other being a male die having a nose portion for cooperation with the female die and at least one adjustable backstop located laterally outwardly of the longitudinal centerline of the die members, a backstop positioning gage comprising: an indexing means formed of a pair of parallel-extending gaging plates, the first plate being adapted to extend over the face of the female die member to engage points on opposite sides thereof and the second plate having a pair of aligned V-shaped notches to engage the nose portion of the male die member thereby establishing a reference plane coplanar with the longitudinal centerline of the male die member; a pair of apertures extending through the lower plate; a sliding guide member in each of the apertures, the upper end of each guide member attached to the upper plate, the guide members maintaining the gaging plates in parallel relation; a pair of blind apertures in the lower plate; a spring in each blind aperture; the upper end of each spring contacting the upper plate; a generally rectangular slot extending through the lower plate perpendicular to the axis of the notches; a scale slidingly mounted in said slot, means to releasably secure the scale in position, indicia aligned with the V-shaped notches on the lower plate, a recess in said lower plate adjacent the indicia; and a reference block which includes the allowance for the bend and the gage of the material to be bent retained in said recess whereby the distance from the outward end of the scale to the outer edge of the reference block establishes the proper distance for the setting of the backstop.

9. The backstop positioning gage specified in claim 8 wherein the means for retaining the reference block in said recess is formed of a counterbore in the plate adjacent the recess, said counterbore having a portion open to the recess; a resilient member positioned in said counterbore, the resilient member extending outwardly into the recess to engage the reference block and resiliently retain it in position.

References Cited UNITED STATES PATENTS 2,638,141 5/1953 Skinner et al. 2,684,538 7/1954 Noe. 2,921,377 1/1960 Hohl. 3,200,508 8/ 1965 Harper.

WILLIAM D. MARTIN, JR., Primary Examiner.

US. Cl. X.R. 33-181 

